The project aims at providing dissociated neural cell systems and cultures mimicking in vitro the properties of the source nervous tissues, so as to be used as models for their investigation. More specifically, the intent is to apply such systems to the study of cellular and humoral influences bearing upon neural development, as exemplified by the interaction of Nerve Growth Factor (NGF) with its target cells. Cultures of dorsal root ganglionic cells will continue to be used to clarify the role of ganglionic glia as an endogenous supplier of a neuron-supportive agent with NGF-like functional and antigenic properties. Intact and dissociated ganglia will be examined for anabolic responses to NGF and other agents, to establish conditions that will permit a finer analysis of sequential events underlying the NGF action.